Computers and printers and many other types of modern electronic equipment often include some type of a printed circuit board assembly. In computers, for example, a printed circuit "motherboard" carries the wiring pattern, electronic parts and the logic and memory integrated circuit chips that control the functions of the computer. In a laser printer, the formatter printed circuit board carries the wiring pattern, electrical parts and integrated circuit chips that control the functions of the printer. During the assembly line manufacture of printed circuit boards, many of the electronic parts, particularly the smaller parts, are mounted on the boards using high speed computer controlled automated machines. These parts are often fed to the mounting machines on a long tape. The tape, which consists of the electronic parts removably affixed to a backing strip, moves from a supply spool, through the mounting machine where the parts are stripped off and installed on the circuit board, to a take-up spool that holds the now empty backing strip.
The spools consist of a center hub sandwiched between two round flat flanges. The tape is wound on the hub (the backing strip only for the take-up spool) between the two flanges. The flanges of the take-up spool are usually contructed as individual pieces that may be separated to expose the hub and make it easier to remove and discard or recycle the backing strip. The two flanges pieces fit together through the mating hub portions that extend out from the inside of each flange. The two pieces are locked together by inserting one hub portion into the other hub portion and then rotating one or both flange pieces clockwise. A slight interference fit between the mating hub portions locks the flange pieces together, that is by screwing them together a fraction of one turn. The flange pieces are released, and may be separated, by rotating the flange pieces counterclockwise, that is, by unscrewing the two hub portions.
The tension on the backing strip as it is wound on to the take-up spool tends to tighten the two flange pieces together. As a result, it is sometimes difficult to release, that is, unscrew and separate the two pieces as necessary to remove and discard the backing strip.